Infection

In Capsule Series Infections

Infections schemeEtiology :

1. Causative organism:

2. Source of infection :

3. Mode of infection :

Clinical picture :

1. Incubation period : Usually 1 – 2 weeks , but in cholera 1 – 5 days.

2. Clinical manifestations .

3. Clinical variants.

4. Complications : specific + ….itis

Investigations :

1. CBC :

2. Culture :

3. Serological tests.

4. Specific :

Differential diagnosis :

1. Specific.

2. PUO ( Pyrexia of Unknown Origin )

Treatment :

a) Prophylaxis :i. Hygienic measures.ii. Case finding.

iii. Isolation & Proper treatment.iv. Chemo & immuno – prophylaxis : ……….

b) Therapeutic :i. General : Rest , light nutrient diet.ii. Symptomatic : antipyretic.

iii. Specific : ………iv. Treatment of complications.

In Capsule Series Infections

TyphoidEtiology :

1. Causative organism: Salmonella typhi & paratyphi A & B

2. Source of infection : Patient , Carrier.

3. Mode of infection : Feco – oral transmission.

Clinical picture :

1. Incubation period : 1 – 2 weeks .

2. Clinical manifestations :

1st week : 10 ( 3 general + 3 respiratory + 3 GIT + rash )

i. Fever : temperature rises in a step ladder manner until reaching

39 – 40o C by the end of the 1st week.

ii. Headache.

iii. Relative bradycardia.

iv. Sore throat.

v. Cough.

vi. Epistaxis.

vii. Coated tongue.

viii. Constipation.

ix. Spleen : palpable , soft & tender.

x. Rash ( rose spot ) : 10%

o Site : Trunk.

o Duration : Transient.

2nd week : ( The same as 1st but severe , no rash )

o Fever : ↑, Continuous

o Headache : ↓with delirium.

In Capsule Series Infections

o Tachycardia.

o Coated tongue .

o Splenic enlargement.

o Diarrhea may occur ( pea soup ).

3rd week : either

o Clinical manifestations start to improve. or

o Complications occur.

4th week :

Convalescence begins ( but relapse may occur )

3. Clinical variants :

o Afebrile.

o Ambulatory.

o Abortive ( mild )

o Grave : ( severe )

o Sudoral form : excessive Sweating.

o Localized : Pleuro typhoid , pneumo typhoid , meningo typhoid.

4. Complications : specific + …itis

o GIT :

Intestinal hemorrhage , Perforation.

Peritonitis , Cholecystitis.

o CNS :

Meningitis , encephalitis , peripheral neuritis.

Typhoid state : delirium , convulsion.

o CVS : myocarditis.

o Chest : Epistaxis , bronchitis .

o Renal : Pyelonephritis , GN.

o Relapse.

In Capsule Series Infections

Investigations :

1. CBC :

o ESR : ↑

o Leucopenia with relative lymphocytosis.

2. Culture :

o Blood culture : +ve in 1st week

o Stool culture : +ve in 2nd week.

o Urine culture : +ve in 3rd week.

3. Specific : ( Widal test )

o It is +ve from 2nd week.

o It is +ve when tre > 1/80

Differential diagnosis : PUO ( Pyrexia of Unknown Origin )

Treatment :

a) Prophylaxis :i. Hygienic measures.ii. Case finding.

iii. Isolation & Proper treatment.iv. Immuno-prophylaxis : TAB vaccine.v. Treatment of carriers :

o Ampicillin : 6 gm/d for 6 weeks.o Cholecystectomy : may be indicated in resistant cases.

b) Therapeutic :i. General : Rest , light nutrient diet.ii. Symptomatic : antipyretic.

iii. Specific : for 2 weeks 3 C Chloramphenicol : 50 mg/kg/d , orally

Ciprofloxacin : 750 mg/12h .

Co-trimoxazole ( septrin ) : 2 tab / 12h.iv. Treatment of complications.

Perforation : surgical treatment. Hemorrhage : blood transfusion & anti-shock measures.

In Capsule Series Infections

BrucellosisEtiology :

1. Causative organism: Brucella , Gm –ve coccobacilli

2. Source of infection :

o Brucella melitenesis : in goats

o Brucella abortus : in cows

o Brucella suis : in pigs.

3. Mode of infection :

o Drinking contaminated milk.

o Dealing with infected animals : farmers , veterinarian.

Clinical picture :

1. Incubation period : 1 – 2 weeks .

2. Clinical manifestations : mnemonic : brucellosis

o Bone & muscle pain.

o Relapsing fever : fever lasts for 10 days then apyrexia for 10 days , then

relapse and so on.

o Constipation , nausea , vomiting.

o Lymph node enlargement.

o Liver : enlarged , tender.

o Spleen : enlarged.

o Sweating.

3. Clinical variants :

o Intermittent.

o Mild.

o Remittent.

o Malignant.

o Continuous

.

o Localized brucellosis e.g. bone , testis.

In Capsule Series Infections

4. Complications :

o Relapse.

o Infective endocarditis. یبوظ القلب و یمنع المشاعر

o Orchitis. یمنع اللي بالي بالك

o Paraplagia due to transverse myelitis. یجیبلك شلل

o Abortion. ......وبعد كل ده لو حصل حاجة

Investigations :

1. CBC : Lymphocytosis , ↑ESR

2. Culture : blood culture +ve during fever spike.

3. Serological tests : Brucella agglutination test.

Differential diagnosis :

1. Fever with lymphadenopathy.

2. PUO ( Pyrexia of Unknown Origin )

Treatment :

a) Prophylaxis : Hygienic measures e.g. Pasteurization of milk.b) Therapeutic :

i. General : Rest , light nutrient diet.ii. Symptomatic : antipyretic & analgesics.

iii. Specific : Tetracycline : 500 mg/6h for 6 weeks. or Doxycyclin : 200 mg/d for 6 weeks. or Septrin : 2 tab /12h for 6 weeks

Plus Streptomycin : 1 gm/d IM for 2 weeks or Rifamicin : 600 mg/12h .

iv. Treatment of complications.

In Capsule Series Infections

MalariaEtiology :

1. Causative organism: Four species affect mankind :

Plasmodium vivax , ovale , malariae & falciparum.

P. falciparum is potentially lethal , the others are usually benign.

2. Source of infection : Patients.

3. Mode of infection : Bite of female anopheles mosquito.

Life cycle :

1) Sexual cycle : in female mosquito. ( exogenous phase )

♀mosquito picks up gametocytes from infected individual → sporzites → migrate to

salivary gland to be injected into man.

2) Asexual cycle : in man ( endogenous phase )

i. Exo-erythrocytic stage : infected mosquito injects sporozytes → which migrate to

liver where they form merozites → Merozites are released to blood stream.

ii. Erythrocytic stage :

Merozites invade the RBCs → signet ring form → Trophozites → rupture of

RBCs releasing merozites which can infect other RBCs.

Clinical picture :

1. Incubation period : 1 – 2 weeks.

2. Clinical manifestations :

i. Benign Tertian malaria : ( infection with P. vivax & ovale )

- The a acks occur every 48 hours.

- The a ack passes into 3 stages :

Cold stage , Hot stage & Sweating stage.

In Capsule Series Infections

a) Cold stage : ( lasts for 1 hour )

o Acute onset of sense of coldness & rigor.

o Rapid rise of temperature to 39 – 40 ᵒC

o Vomiting & polyuria.

b) Hot stage : ( lasts for 8 hours )

o Hotness & flushed face.

o Headache.

o High temperature.

c) Swea ng stage : ( lasts for 3 hours )

o Sweating with rapid fall of temperature with no or mild

vomiting.

o Spleen is enlarged a er 2 weeks.

ii. Quartan malaria : ( infection with P.malariae )

Similar to benign ter an malaria but the a acks occur every 72 hours.

iii. Malignant malaria : ( infection with P. falciparum )

a) Ordinary tertian type :

Clinical manifestations are similar to benign tertian malaria but :

Hot stage is prolonged.

Sweating stage : ↓

Splenomegaly occurs within less than 1 week.

b) Pernicious type : ( complicated – fatal )

i. Algid malaria : Abdominal pain , shock , hypothermia.

ii. Bilious remittent fever : Jaundice , vomiting , gastric pain.

iii. Cerebral malaria : Headache , Hyperpyrexia , Focal

neurological disorders , Psychosis.

iv. Dysenteric type : dysentery.

In Capsule Series Infections

c) Blackwater fever :

o Blackwater fever is a complication of malaria characterized by

intravascular hemolysis, hemoglobinuria and acute renal failure.

o Quinine – anti-malarial drug – may play a role in triggering the

condition.

o Most probably autoimmune ?

o Clinical picture :

i. Hemolysis : Fever , rigor , anemia , jaundice.

ii. Hemoglobinuria : dark red or black urine ( hence the name ) ,

loin pain.

iii. Acute renal failure : due to massive intravascular hemolysis

3. Complications of malaria :

Malignant malaria : ( complications of P. falciparum )

i. Pernicious malaria : ABCD

ii. Blackwater fever : Hemolytic anemia , acute renal failure.

Relapse : in P. ovale & vivax. ( No relapse in P falciparum )

Rupture of spleen.

Tropical splenomegaly syndrome.

Malarial hepatitis syndrome ( easily mistaken clinically for viral hepatitis )

Nephrotic syndrome : especially in quartan malaria ( P. malariae )

Investigations :

1. Detection of the parasite : blood film , bone marrow aspirate.

2. CBC : Features of hemolytic anemia. Leucocytosis during the attack.

3. Serological tests : to detect antibodies.

4. Therapeutic test: fever responds to anti-malarial drugs.

5. Investigations for complications : e.g. Acute renal failure.

In Capsule Series Infections

Differential diagnosis :

1. Fever with rigor.

2. PUO ( Pyrexia of Unknown Origin )

Treatment :

a) Prophylaxis :i. Hygienic measures ( Anti-mosquto measures ) :

Insecticides , bed nets , repellants.

ii. Chemo prophylaxis : when travelling to endemic areas.

Chloroquine : 500 mg/week, one week before arriving and 4 weeks after leaving

Others : primaquine , mefloquine , proguanil.

b) Therapeutic :

Active malaria infection with P. falciparum is a medical emergency requiring hospitalization. Infection

with P. vivax, P. ovale or P. malariae can often be treated on an outpatient basis.

i. General : Rest , light nutrient diet.

ii. Symptomatic : antipyretic.

iii. Specific : ( Anti-malarial drugs )

a) Tissue schizonticides ( against exoerythrocytic form ) :

for preventing relapse e.g.

Primaquine.

Pyrimethamine.

b) Blood schizonticides :

These drugs act on the erythrocytic forms of the parasite and

terminate clinical attacks of malaria. These are the most important

drugs in anti malarial chemotherapy e.g.

Chloroquine :

- Dose : 4 tab at first ( tab = 250 mg ) , then 2 tab a er 12 h then 2

tab/d for 2 successive days.

In Capsule Series Infections

- Side effects : Corneal opacity , GIT irritation , Itching.

- Contra indications: Chloroquine should be used with caution in

patients with hepatic disease.

Quinine :

Dose : 650 mg t.d.s. for 1 week

Side effects : Cinconism ( nausea , vomiting , tinnitus ) , Hemolytic

anemia.

Mefloquine.

Fansidar ( compination of pyrimethamine & sulphadoxine )

3 tab as a single dose.

iv. Treatment of complications : e.g. blackwater fever

o Acute renal failure : dialysis.

o Blood transfusion.

o Cortisone.

Throughout nature, infection without disease is the rule rather than the exception.

Rene Dubos

In Capsule Series Infections

Infectious mononucleosis( Glandular fever )

Etiology :

1. Causative organism: Epstein – Barr virus.

2. Source of infection : Carriers , Patients.

3. Mode of infection : Kissing , droplets infections.

Clinical picture :

1. Incubation period : 1 – 2 weeks.

2. Clinical manifestations :

o Asymptomatic.

o Fatigue.

o Sore throat , tonsillitis . pharyngitis.

o Fever : is usually present and is low grade.

o Enlarged LN , spleen & liver.

o Transient rash on ampicillin therapy.

o Periorbital edema.

3. Clinical variants :

o Glandular type.

o Aglandular type : especially in elderly patients.

o Febrile type : with high fever.

o Ictric type : with jaundice , especially in elderly patient.

o Encephalitic type.

4. Complications :

o Liver : hepatitis.

o Spleen : Rupture.

o Blood : Autoimmune hemolytic anemia , thrombocytopenia.

In Capsule Series Infections

o CNS : Meningitis, encephalitis, transverse myelitis , Guillain-Barré

syndrome. EBV infection has also been proposed as a risk factor for the

development of multiple sclerosis but this has not been confirmed.

Investigations :

1. CBC :

2. Culture :

3. Serological tests.

4. Specific :

Differential diagnosis :

1. Specific.

2. PUO ( Pyrexia of Unknown Origin )

Treatment :

a) Prophylaxis :i. Hygienic measures.ii. Case finding.

iii. Isolation & Proper treatment.iv. Chemo & immuno – prophylaxis : ……….

b) Therapeutic :i. General : Rest , light nutrient diet.ii. Symptomatic : antipyretic.

iii. Specific : ………iv. Treatment of complications.